[QE-users] k-point algorithm is not tested yet turbo davidson

Fri Dec 20 18:32:52 CET 2019

Dear Iurii,

Many thanks. It seems that turbo_eels does not work with nspin = 2. It
gives an error:

Error in routine lr_readin (1):
LSDA is not implemented

But it does work without npsin = 2 but with smearing and tot_charge =
0/-1/+1

Best,
Abhirup
-------------------------------------------------------------------------------------------------------------------------------------
Abhirup Patra
Postdoctoral Research Fellow
Department of Chemistry
University of Pennsylvania

On Thu, Dec 19, 2019 at 11:49 AM Timrov Iurii <iurii.timrov at epfl.ch> wrote:

> Dear Abhirup,
>
>
> Thank you for clarifications!
>
>
> Please note that the turbo_eels code works for the noncollinear
> spin-polarization (noncolin=.true.), and including the spin-orbit coupling
> (if needed). The turbo_eels code works for the general k-points
> implementation (k=0 is allowed), but it does not work for the "gamma_only"
> case (i.e. using tricks to speed up calculations).
>
>
> The turbo_lanczos and turbo_davidson codes (which are for the absorption
> spectroscopy) do not work in the spin-polarized case (both collinear and
> noncollinear) - yes, you are right.
>
>
> Best,
>
> Iurii
>
>
> --
> Dr. Iurii Timrov
> Postdoctoral Researcher
> STI - IMX - THEOS and NCCR - MARVEL
> Swiss Federal Institute of Technology Lausanne (EPFL)
> CH-1015 Lausanne, Switzerland
> +41 21 69 34 881
> http://people.epfl.ch/265334
> ------------------------------
> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
> Abhirup Patra <abhirupp at sas.upenn.edu>
> *Sent:* Thursday, December 19, 2019 5:40:47 PM
> *To:* Quantum ESPRESSO users Forum
> *Subject:* Re: [QE-users] k-point algorithm is not tested yet turbo
> davidson
>
> Dear Iurii,
>
> Thanks for the email. Sorry about not explaining it well. Here is what I
> meant: With spin-polarization and with gamma only kmesh none of the TDDFT
> code works (i.e. turbo_davidson, turbo_eels, turbo_lanczos). So it is
> difficult to simulate optical spectra for a "neutral (tot_charge = 0)"
> doped/defected structure. By "works", I meant that I could run the regular
> scf-calculation and TDDFT codes for any "non-zero (tot_charge = -1 or +1)"
> charged structure using "gamma only" kmesh and "non spin-polarization".
>
> Please let me know if it's still confusing.
>
> Best,
> Abhirup
>
>
>
> -------------------------------------------------------------------------------------------------------------------------------------
> Abhirup Patra
> Postdoctoral Research Fellow
> Department of Chemistry
> University of Pennsylvania
>
>
> On Thu, Dec 19, 2019 at 4:06 AM Timrov Iurii <iurii.timrov at epfl.ch> wrote:
>
>> Dear Abhirup,
>>
>>
>> Sorry, I miss the point. Could you clarify please what do you mean by
>> saying "it works"? Do you refer to the k-points implementation of the
>> turbo_davidson code or something else? The k-points algorithm must be
>> disabled for all cases (neutral and charged cases), and if this not the
>> case, then I will modify the code in order to disable it.
>>
>>
>> Best,
>>
>> Iurii
>>
>>
>> --
>> Dr. Iurii Timrov
>> Postdoctoral Researcher
>> STI - IMX - THEOS and NCCR - MARVEL
>> Swiss Federal Institute of Technology Lausanne (EPFL)
>> CH-1015 Lausanne, Switzerland
>> +41 21 69 34 881
>> http://people.epfl.ch/265334
>> ------------------------------
>> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
>> Abhirup Patra <abhirupp at sas.upenn.edu>
>> *Sent:* Wednesday, December 18, 2019 9:36:51 PM
>> *To:* Quantum ESPRESSO users Forum
>> *Subject:* Re: [QE-users] k-point algorithm is not tested yet turbo
>> davidson
>>
>> Forgot to mention, it only happens if I do not assign any charge to the
>> structure i.e., for neutral case. However, it works for nonzero tot_charge,
>> spin-unpolarized situation with fixed smearing and turb_davidson works fine.
>>
>> Thanks for your comments.
>>
>> Best,
>> Abhirup
>>
>> -------------------------------------------------------------------------------------------------------------------------------------
>> Abhirup Patra
>> Postdoctoral Research Fellow
>> Department of Chemistry
>> University of Pennsylvania
>>
>>
>> On Wed, Dec 18, 2019 at 3:29 PM Abhirup Patra <abhirupp at sas.upenn.edu>
>> wrote:
>>
>>> Thanks, Iurii. Yes, the spectrum with gamma point is quite reasonable
>>> but do not match with the experimental observation. It could be some other
>>> issue.
>>>
>>> However, I am wondering how to do the TDDFT calculation for a
>>> doped/defected structure with extra electron or hole. I tried to use
>>> turbo_davidson starting from i) scf calculation with npsin= 2 and total
>>> magnetization and turbo_davidson does not work since I believe it does not
>>> for spin-polarized system, then, I tried ii) scf calculation without any
>>> spin-polarization and the scf calculation did not run since it cannot work
>>> with an extra charge and 'fixed' occupation, and, finally, iii) scf with
>>> smearing but turbo_davidson does not support scf calculation with smearing
>>> (ref:
>>> https://lists.quantum-espresso.org/pipermail/users/2017-January/037363.html)
>>>
>>>
>>> I believe in this case I cannot use TDDFT of QE to calculate absorption
>>> spectra of a defected or doped structure. Am I right here?
>>>
>>> Best,
>>> Abhirup
>>>
>>>
>>>
>>> -------------------------------------------------------------------------------------------------------------------------------------
>>> Abhirup Patra
>>> Postdoctoral Research Fellow
>>> Department of Chemistry
>>> University of Pennsylvania
>>>
>>>
>>> On Wed, Dec 18, 2019 at 4:00 AM Timrov Iurii <iurii.timrov at epfl.ch>
>>> wrote:
>>>
>>>> Dear Abhirup,
>>>>
>>>>
>>>> > However, I am not sure with the number of atoms (~120 or more) GW-BSE
>>>> calculations with supercell is actually feasible.
>>>>
>>>>
>>>> Yes, I understand the issue. I do not know if it is feasible. You may
>>>> try to use e.g. Yambo and see how it goes. Otherwise, since you have
>>>> already quite a big cell, maybe with k=0 you obtain quite a reasonably
>>>> converged spectrum (to be checked w.r.t. the cell size)  at the TDDFT level
>>>> in the adiabatic approximation.
>>>>
>>>>
>>>> Regards,
>>>>
>>>> Iurii
>>>>
>>>>
>>>> --
>>>> Dr. Iurii Timrov
>>>> Postdoctoral Researcher
>>>> STI - IMX - THEOS and NCCR - MARVEL
>>>> Swiss Federal Institute of Technology Lausanne (EPFL)
>>>> CH-1015 Lausanne, Switzerland
>>>> +41 21 69 34 881
>>>> http://people.epfl.ch/265334
>>>> ------------------------------
>>>> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
>>>> Abhirup Patra <abhirupp at sas.upenn.edu>
>>>> *Sent:* Tuesday, December 17, 2019 4:47:01 PM
>>>> *To:* Quantum ESPRESSO users Forum
>>>> *Subject:* Re: [QE-users] k-point algorithm is not tested yet turbo
>>>> davidson
>>>>
>>>> Thanks very much, Iurii. I really appreciate your answer and it does
>>>> make sense to me. With gamma point only it works fine. And, you are  right,
>>>> my system is a solid and I am
>>>> trying to simulate the optical spectrum. However, I am not sure with
>>>> the number of atoms (~120 or more) GW-BSE calculations with supercell is
>>>> actually feasible.
>>>>
>>>> Best,
>>>> Abhirup
>>>>
>>>> -------------------------------------------------------------------------------------------------------------------------------------
>>>> Abhirup Patra
>>>> Postdoctoral Research Fellow
>>>> Department of Chemistry
>>>> University of Pennsylvania
>>>>
>>>>
>>>> On Tue, Dec 17, 2019 at 7:50 AM Timrov Iurii <iurii.timrov at epfl.ch>
>>>> wrote:
>>>>
>>>>> Dear Abhirup,
>>>>>
>>>>>
>>>>> As you can see from the error message of the turbo_davidson code, the
>>>>> k-points algorithm is not supported. Only Gamma point sampling can be used.
>>>>>
>>>>>
>>>>> If I understand correctly, your system is a solid, right? And you want
>>>>> to use a unit cell with a k-points mesh, right? The turbo_davidson cannot
>>>>> be used in this case. You may try to use a supercell with a Gamma point
>>>>> sampling. But be careful when using TDDFT in the adiabatic approximation
>>>>> for the absorption spectroscopy of solids. I recommend that you check
>>>>> literature on this topic. Maybe you will need to resort to the BSE approach.
>>>>>
>>>>>
>>>>> HTH
>>>>>
>>>>>
>>>>> Iurii Timrov
>>>>>
>>>>>
>>>>> --
>>>>> Dr. Iurii Timrov
>>>>> Postdoctoral Researcher
>>>>> STI - IMX - THEOS and NCCR - MARVEL
>>>>> Swiss Federal Institute of Technology Lausanne (EPFL)
>>>>> CH-1015 Lausanne, Switzerland
>>>>> +41 21 69 34 881
>>>>> http://people.epfl.ch/265334
>>>>> ------------------------------
>>>>> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
>>>>> Abhirup Patra <abhirupp at sas.upenn.edu>
>>>>> *Sent:* Monday, December 16, 2019 6:12:08 PM
>>>>> *To:* Quantum ESPRESSO users Forum
>>>>> *Subject:* [QE-users] k-point algorithm is not tested yet turbo
>>>>> davidson
>>>>>
>>>>> Hello,
>>>>>
>>>>> I am trying to use turbo_davidson starting from a SCF calculation
>>>>> using PBE without smearing and spin-polarization. This system is a
>>>>> non-metal with bandgap of 2.6 eV. I gave uniform k-mesh as follows for the
>>>>> bcc structure with lattice constant of 10.34 angstrom.
>>>>>
>>>>>  K_POINTS {crystal_b}
>>>>>  9
>>>>> 0.0 0.0 0.0 0
>>>>> 0.0 -0.5 0.0 0
>>>>> 0.0 -0.5 0.5 0
>>>>> 0.5 -0.5 0.5 0
>>>>> 0.5 -0.5 0.0 0
>>>>> 0.5 0.0 0.0 0
>>>>> 0.0 0.0 0.0 0
>>>>> 0.0 0.0 0.5 0
>>>>> 0.5 0.0 0.5 0
>>>>>
>>>>> &lr_input
>>>>>     prefix = 'pristine_pbe'
>>>>>     outdir = './'
>>>>> !    wfcdir = './'
>>>>> /
>>>>> &lr_dav
>>>>>   num_eign = 35,
>>>>>   num_init = 70,
>>>>>   num_basis_max = 200,
>>>>>   start = 0.0d0
>>>>>   finish = 3.5d0
>>>>>   step = 0.001d0
>>>>>   broadening = 0.005d0
>>>>> /
>>>>>
>>>>> However, I am getting the following error:
>>>>>
>>>>>      Error in routine lr_readin (1):
>>>>>      k-point algorithm is not tested yet
>>>>>
>>>>> I am wondering if there is a simple way out to this problem other than
>>>>> explicitly testing different k mesh combinations.
>>>>>
>>>>> Best,
>>>>> Abhirup
>>>>>
>>>>> -------------------------------------------------------------------------------------------------------------------------------------
>>>>> Abhirup Patra
>>>>> Postdoctoral Research Fellow
>>>>> Department of Chemistry
>>>>> University of Pennsylvania
>>>>> _______________________________________________
>>>>> Quantum ESPRESSO is supported by MaX (
>>>>> www.max-centre.eu/quantum-espresso)
>>>>> users mailing list users at lists.quantum-espresso.org
>>>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>>>
>>>> _______________________________________________
>>>> Quantum ESPRESSO is supported by MaX (
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>>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>>
>>> _______________________________________________
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>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
> _______________________________________________
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